Flat panel display having integral heater, EMI shield, and thermal sensors

ABSTRACT

A flat panel display having a black mask EMI layer isolated from Vcom and tied to zero potential. The flat panel display has an integral metal heater layer and thermal sensor that are in close proximity to the liquid crystals to provide efficient heating and temperature sensing.

This application is a continuation-in-part of pending U.S. applicationSer. No. 10/679,977, filed on Oct. 7, 2003.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a liquid crystal flat panel display.More particularly, in one embodiment, the flat panel display of thepresent invention has layers of Indium Tin Oxide (ITO), or otheroptically transparent electrically conductive materials, coated on thefront and rear external glass surfaces under the front and rearpolarizers. The ITO layer at the front of the display acts as anelectromagnetic interference (EMI) filter or shield. The ITO layer atthe back of the display is used as a heater. Each ITO layer may or maynot be overcoated on one or both sides with index matching dielectricsto improve optical transmission through the ITO coatings, and/or reducethe optical reflections at the front and/or rear surfaces of the ITOlayers.

In an alternative embodiment, the ITO heater layer is placed on theinside surface of the rear glass plate allowing the ITO heater layer tobe closer to the liquid crystal layer. This reduces the thermalresistance between the ITO layer and the liquid crystal layer thusreducing the amount of power necessary to heat the liquid crystal layer.In the preferred embodiment, bus bars are placed along predeterminededges of the ITO heater layer. The bus bars allow for the uniforminjection of current into the ITO heater layer. It is also preferredthat thermal sensors be placed on the inside portion of the glass and inclose proximity to the ITO layer to detect the heat being inputted intothe liquid crystal layer.

In another alternative embodiment, an integral metal heater is usedinstead of the ITO heater layer. The metal heater is applied to the TFTlayer and is in close proximity to the liquid crystal layer to provideimproved and efficient heating capabilities.

In another alternate embodiment, a black mask EMI layer is interposedbetween the front and back glass plates. In the preferred embodiment,the EMI layer is isolated from Vcom and tied to zero potential. It ispreferred that the integral metal heater be placed behind the black maskEMI layer so that no portion of the heater is visible and no portion ofthe heater interferes with the pixel apertures.

In another alternate embodiment, integral thermal sensors may also belayered onto the TFT array layer preferably under the black mask EMIlayer. In this embodiment, thermal resistivity between the integralheater and the thermal sensor(s) is reduced leading to faster thermalsensor response times. It is appreciated, as discussed in further detailbelow, that features of the alternate embodiments discussed above may becombined to form additional alternative flat panel display designs. Forexample, a flat panel display may be configured with all of theinventions of the isolated black mask EMI layer, integral thermal sensorand integral heater combined in one flat panel display.

In addition to the features mentioned above, objects and advantages ofthe present invention will be readily apparent upon a reading of thefollowing description.

BRIEF DESCRIPTION OF THE DRAWINGS

Novel features and advantages of the present invention, in addition tothose mentioned above, will become apparent to those skilled in the artfrom a reading of the following detailed description in conjunction withthe accompanying drawings wherein similar reference characters refer tosimilar parts and in which:

FIG. 1 illustrates a known flat panel display system;

FIG. 2 illustrates one embodiment of the flat panel display of thepresent invention;

FIG. 3 illustrates an alternative embodiment of the flat panel displayof the present invention;

FIG. 4 illustrates an alternative embodiment of the flat panel displayof the present invention;

FIG. 5 illustrates a plan view of one example of a flat panel display ofthe present invention showing flexible TCP connections;

FIG. 6 illustrates a perspective blow-up view of one embodiment of adisplay incorporating the flat panel display of the present invention;

FIG. 7 illustrates a plan view of one embodiment of the black mask EMIshield layer of the present invention;

FIG. 8 illustrates a plan view of one embodiment of a metal heater layerof the present invention;

FIG. 9 illustrates one example embodiment of a heater circuit of thepresent invention;

FIGS. 10A-B illustrate other integral heater designs;

FIG. 11 illustrates one embodiment of a TFT design of the presentinvention with integral heater;

FIG. 12 illustrates one embodiment of a thermal sensor diode array ofthe present invention;

FIG. 13 illustrates a plan view of a flat panel display showing thermalsensor placement;

FIG. 14 illustrates an example block diagram of the electricalcomponents and connections of a display incorporating the flat paneldisplay of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

The preferred system herein described is not intended to be exhaustiveor to limit the invention to the precise forms disclosed. They arechosen and described to explain the principles of the invention, and theapplication of the method to practical uses, so that others skilled inthe art may practice the invention.

FIG. 1 illustrates a known display system. In known flat panel displays,the polarizer layers are placed directly on the front and back plates.FIG. 2 illustrates one embodiment of the flat panel display 10 of thepresent invention. According to known flat panel display technology, thedisplay is comprised of a front plate 12 and a back plate 14. In oneembodiment of the present invention, layers of Indium Tin Oxide (ITO)layers 18, 20 (with or without additional index of refraction matchingdielectric layers) are placed between the outside surfaces of the frontand back plates and the polarizer layers 16. In one embodiment, thefront plate is a liquid crystal display (LCD) color filter (CF) plateand the back plate is an LCD thin film transistor (TFT) plate. In oneembodiment the front and back plates are transparent glass substrates.According to known principles, a layer of liquid crystals are placedbetween the plates.

In the embodiment of FIG. 2, the front EMI shield ITO coating 18 ispreferably a constant ≦15-20 ohms/sq value. A first index matchingdielectric layer 22 may be placed between the EMI shield ITO layer andthe front polarizer layer. A second index matching dielectric layer 24may be placed between the EMI shield ITO layer and the front plate. Whenelectrically bonded or grounded to the associated metal or electricallyconductive chassis of the complete LCD assembly and/or its associatedproduct chassis, this front ITO coating acts as an EMI shield. This ITOEMI shield significantly reduces radiated emissions originating from theLCD itself, as well as shields, or reduces the susceptibility of, theLCD from the effects of externally imposed electromagnetic fields.

In the embodiment of FIG. 2, the rear heater ITO coating 20 ispreferably sandwiched between a first index matching dielectric layer 26and a second index matching dielectric layer 28. The first indexmatching dielectric layer 26 may be placed between the heater ITO layerand the rear polarizer layer. The second index matching dielectric layer28 may be placed between the heater ITO layer and the back plate. Theindex matching layers are for matching the index of refraction betweenthe heater ITO layer and the glass and between the heater ITO layer andthe Pressure Sensitive Adhesive (PSA) layers 40, 42 of the polarizer,respectively. Index matching helps keep the specular reflection to anabsolute minimum, which also increases the optical transmission of theentire optical stack. The rear ITO layer is actively driven by circuitryto function as a heater. The ohm/sq value of this ITO layer may vary asdesired based on performance needs and size variables.

In the preferred embodiment of FIG. 2, the outer edges 30 of the frontITO layer and the front plate extend past (e.g., 0.25-0.50 mm) the outeredges 32 of the front polarizer and first dielectric layer (if present)18. This exposes the front ITO layer for electrical contact outboard ofthe polarizer edges. Similarly, two opposed outer edges 34 of the backITO layer and the back plate extend past the outer edges 36 of the backpolarizer layer and the dielectric layer (if present) 20. Thus the ITOlayer is exposed for connection of the drive circuitry for the heaterfunction.

Placing the ITO layers and the index matching layers between thepolarizers and the LCD plates provides advantages over known flat paneldisplays (i.e., current known processes apply the coatings on separateglass plates (not directly on the LCD plates). The separate front EMIplate can be mounted free standing in front of the LCD or laminated withoptical adhesive directly to the front polarizer of the LCD. Theseparate rear heater plate is laminated with optical adhesive directlyto either the front or rear polarizer of the LCD in order to facilitateadequate heat transfer from the ITO heating layer to the liquid crystalfluid. In some known configurations, the heater ITO is decoupled (radiofrequency (RF)) to the chassis ground of the LCD, so that it functionsas both the EMI shield and the heater. In these cases, the heaterelement is typically laminated to the front polarizer of the LCD.

Placing the ITO layers, with or without index matching layers, directlyon the plates results in significant cost, weight, and thicknesssavings, as well as improved optical performance. The process embodiedin this invention also provides a more efficient coupling of the heaterITO to LCD fluid, reducing the power density required to heat the LCDfluid to a given temperature over a given period of time. This improvedcoupling results from having the ITO heater coated directly on thesurface of the LCD glass, thereby eliminating the thermal resistancecaused in known implementations by the optical adhesive, polarizer andpolarizer PSA. In typical known configurations, a power density of 2watts per square inch of display image area is required to heat the LCDfluid from −54° C. to −20° C. in ≦10 minutes. With the ITO coateddirectly on the rear surface of the LCD, this same heating of the LCDfluid can be accomplished with a power density of 1.8 watts per squareinch of display image area.

In known flat panel display systems, where ITO layers are coated onseparate glass plates that are then laminated to the outside of thepolarizer, the lamination process often results in layers that containbubbles or particulates. Displays having bubble or particulatecontamination are scrapped as unsatisfactory displays. Because thecontamination is not detectable until the adhesive is dry and thedisplay is fully assembled, a contaminated laminate layer results in theloss of an entire LCD assembly. Coating the ITO, with or without indexmatching layers, directly on the external front and rear surfaces of theLCD glass (i.e., plates) avoids this high yield loss.

Placing the index matching ITO layers directly on the plates alsoprevents the undesirable effects of lamination-induced window framing(LIWF). In known flat panel displays, the ITO layers are coated directlyonto separate glass plates, which are typically then laminatedpermanently with optical adhesive to the external surfaces of the frontand/or rear polarizer(s). Due to the shrinkage of the optical adhesiveduring its cure, and/or differential coefficients of thermal expansion(Cte) of the ITO cover glass(es), optical adhesive, polarizer and LCDglass, the LCD glass bends or bows, changing the cell gap between thefront and rear glass plates of the LCD. This cell gap deformationlocally changes the image contrast, typically causing “whitening” or“darkening” degradation of contrast around the edge or periphery of thedisplay area (i.e., “halo” effect). This effect is known as LIWF. Theseverity of this degradation changes with the age and operatingtemperature of the display. By skipping the step of laminating ITOcoated glass plates to the outside surface of the polarizer layer, LIWFis avoided.

Placing the index matching ITO layers directly on the plates alsoenhances optical performance. The present invention has a reducedspecular reflection and increased contrast over known displays whichhave ITO coated glass plates laminated to the outside surface of thepolarizers. By placing the front ITO layer under the front polarizerlayer, less light is reflected from the display. In other words, becausethe front polarizer is transmitting only a portion of the light from theoutside (e.g., 42% of the light is transmitted by the polarizer), acorresponding smaller amount of that transmitted light is reflected bythe ITO layer between the polarizer and the front plate.

The ITO layers and the index matching dielectric layers of the presentinvention are applied using known manufacturing processes such assputtering or vapor deposition.

FIG. 3 illustrates another embodiment of a flat panel display 50 of thepresent invention. In this embodiment, the display is preferablycomprised of the following layers: a front polarizer 52, a pressuresensitive adhesive layer 54, an LCD color plate or glass layer 56, ablack mask layer 58 (preferably chrome), a color filter layer 60, a VcomITO 62, a first and second Polyamide Alignment Layer 64, a layer ofliquid crystals 65, a TFT array layer 66, and insulator layer 68, an ITOheater layer 70, a LCD TFT plate or glass 72, a second pressuresensitive adhesive layer 74, a rear polarizer layer 76, andanti-reflective coating layers 78.

In the embodiment of FIG. 3, the ITO heater layer is preferably placedon the inside surface of the glass plate allowing the ITO heater layerto be closer to the liquid crystal layer. This reduces the thermalresistance between the ITO layer and the liquid crystal layer thusreducing the amount of power necessary to heat the liquid crystal layer.Furthermore, since there are fewer intervening layers between the ITOheater and the liquid crystal layer, less power is needed to heat theliquid crystal layer. Because of the lower power requirements forpowering the ITO layer, the ohms/square and therefore thickness ordensity of the ITO may be reduced, thereby increasing the opticaltransmission.

In the preferred embodiment of FIG. 3, bus bars are placed alongpredetermined edges of the ITO heater layer. The bus bars provide a lowimpedance connection along predetermined edges of the ITO heater layer.The bus bars allow for the uniform injection of current into the ITOheater layer. In one embodiment, silk screen epoxy is laid onto the ITOheater layer which is then placed in an oven and heated. Accordingly,the resulting bus bars become embedded into the ITO layer.

In this embodiment, it is preferred that the black mask layer,preferably comprised of chrome, be electrically tied to the zeropotential chassis. Accordingly, the black mask layer acts as an EMIlayer. In an alternate embodiment, index matching dielectric layers canbe sandwiched around the ITO heater layer to provide the benefitsdiscussed earlier. The insulator layer could also be used as an indexmatching dielectric layer. In one embodiment, the black mask layer isapplied through known vapor deposition or sputtering techniques.

FIG. 4 illustrates another alternative embodiment of the flat panelglass and display illustrated in FIG. 3. FIG. 4 is the preferredembodiment of the flat panel display of the present invention. In thepreferred embodiment, the LCD is a TFT active matrix liquid crystaldisplay (AMLCD) with source and gate drive flexible tape carrier package(TCP) connections 84. In the embodiment of FIG. 4, the heater layer 80and thermal sensors (shown generally at 82) are integral to the flatpanel display as they are applied to the TFT array structure. The flatpanel display of FIG. 4 avoids the high yield loss and LIWF issues ofthe prior art displays as previously discussed.

In the embodiment of FIG. 4, the LCD is comprised of a black mask EMIshield interposed between the front and rear glass plates. LCDs radiateEMI (radiated emissions) and are also susceptible to high strength EMIfields (radiated susceptibility). To guard against these EMI problems insensitive environments (i.e., military applications, aircraftapplications, etc.), an optically transmissive, low electricalresistance layer is used to cover the entire active area of thedisplayed image. Historical solutions have involved optically laminatingor bonding a cover glass to the front of the LCD that has either beencoated with an 8-20 ohm/square Indium Tin Oxide (ITO) layer or containsa low resistance black oxide wire mesh. The EMI shield absorbs andconducts the interference signal from the display. Using a cover glassis costly and electrical termination is labor intensive due to the useof electrically conductive bus bars and associated wire/foil leads. Theuse of cover glasses also creates optical problems because the ITO orwire mesh—reduces optical transmission and increases ambient lightreflections that both contribute to reduced image luminance andcontrast. To compensate for the reduced luminance and contrast, higherintensity backlights are used which leads to greater system costs,higher display operating temperature (reduced life) and greater systempower consumption (more increased system costs). Furthermore, with wiremesh, image moiré (i.e., optically distracting black and white movingpattern caused by optical interference between the mesh and pixelstructures) can never be eliminated.

In the preferred embodiment of the black mask EMI shield, the gate,source, heater bus lines, pixel capacitors, and pixel feed-throughs arecovered by the low reflection, electrically conductive (e.g., less thanor equal to 10.0 ohms/square) black mask when viewed from any angle,preferably over the entire viewing area. Electrical connection to theblack mask is preferably accomplished through the source TCPs andthrough a flex printed circuit (FPC) across the display.

The black mask is preferably applied with the known process ofsputtering or evaporating (i.e., vacuum deposition). The layers arepreferably applied to reduce the ohms/square resistance fromapproximately 20-30 ohms/square to 8-10 ohms/square. Accordingly, in thepreferred embodiment, the black mask is the very first layer depositedand adhered to the inside of the front plate (i.e., color plate) of theLCD. Vcom, on most LCD panels, is some positive voltage around 4-7volts. By isolating the black mask from Vcom, the Vcom electricalpotential (and normal functions of the LCD) is left undisturbed. Byconnecting the black mask to chassis ground, a low DC and RF (radiofrequency) resistance/impedance Faraday cage or EMI shield isestablished between the “outside” world and the TFT transistors of theLCD. Therefore, the isolated and chassis grounded black mask forms anEMI shield between the active electronics of the LCD and the outsideworld. This reduces the radiated emissions from the LCD panel, as wellas increases the resistance of the LCD panel to radiated susceptibility(i.e., image degradation caused by the influence of external electricalfields), without having to add some external feature (i.e., a laminatedITO coated piece of cover glass). In addition, since the black mask doesnot cover or obscure the active pixel aperture, the integral EMI shielddoes not reduce any light transmission through the LCD (i.e., anexternally laminated ITO coated piece of glass has less than 100%optical transmission and thereby reduces light transmission thought theLCD). Also, an externally laminated ITO piece of cover glass has aspecular and diffuse reflection of >0.0%, thereby increasing thereflectivity of the LCD, which reduces image contrast (particularly whencombined with the reduced light transmission of the laminated coverglass). None of these optical degradations occur with our integral EMIshield (i.e., no increase in specular and diffuse reflectance, noreduction in LCD optical transmission, and no reduction in imagecontrast).

The black mask (BM) EMI shield of the present invention uses an existingstructure within the LCD to perform an additional function. Other thanthe very low cost addition of an optically clear resin dielectric(insulating) layer 83 between the black mask and the Vcom ITO (alreadyexisting structures within the LCD) there are no items added to degradethe image quality.

FIG. 5 illustrates one example embodiment of a flat panel display havingflexible TCP connections. Connections to the internal EMI shield areaccomplished through the TCP. In this example embodiment, heaterchannels: 4-60, 89-145, 174-230, 259-315 (total: 228 channels); blackmask channels: 65-84, 150-169, 235-254 (total: 60 channels); dummychannels: 1-3, 61-64, 85-88, 146-149, 170-173, 231-234, 255-258, 316-318(total: 30 channels) are used. The source and gate drive flexible tapecarrier package (TCP) connections are shown at 84. The EMI bonding padsare illustrated at 86. FIG. 6 illustrates a perspective blow-up view ofone embodiment of the flat panel display of the present inventionillustrating the TCP connections.

FIG. 7 illustrates a plan view of one embodiment of the black mask EMIshield layer of the present invention. It is preferred that the blackmask resistivity be <10 ohms per square. In one embodiment the blackmask is comprised of a CrOx/CrNx/Cr, 350/350/1020A, layer.

In the embodiment of FIG. 4, an integral metal heater 80 (shown inblack) is used instead of the ITO heater layer. In the preferredembodiment, metal heater is patterned on top of the passivation layer ofthe thin film transistors (TFTs) and then overcoated with anotherpassivation layer to electrically isolate the metal layer from the pixelcapacitors. Because the heater layer is closer to the liquid crystallayer, thermal resistance is reduced between the heater and the liquidcrystal layer thus reducing the amount of power necessary to heat theliquid crystal layer. Again, since there are fewer intervening layersbetween the heater and the liquid crystal layer, less power is needed toheat the liquid crystal layer.

FIG. 8 illustrates a plan view of one embodiment of a metal heater layerof the present invention. It is preferred that the integral metal heaterbe hidden behind the black mask EMI layer so that no portion of theheater is visible and no portion of the heater interferes with the pixelapertures. The LCD liquid crystal (LC) fluid is heated to preserveresponse time (i.e., prevent image smearing of rapid image movement) atlower display module temperatures (usually somewhere below 0 degreesC.). To accomplish this, historic solutions have involved opticallylaminating or bonding a cover glass to the front or rear of the LCD thatis coated with an Indium Tin Oxide (ITO) layer whose electricalresistance is selected to produce a power dissipation of typically 2watts/square inch of image area when the heater voltage is applied. Thistypical method is costly (e.g., the heater glass is expensive) andelectrical termination is labor intensive (i.e., required electricallyconductive bus bars and associated wire/foil leads). Furthermore, thetypical heating technologies are prone to handling damage resulting inunusable LCDs. These historic heater technologies also created opticalproblems due to reduced optical transmission and increased ambient lightreflections. Accordingly, these typical LCDs have reduced imageluminance and contrast.

The integral metal heater of the present invention is comprised ofstructure within the LCD to perform the heater function. The integralmetal heater is preferably made by two additional photolithographysteps, which does increase the cost of the LCD cell, but to only afraction of the cost of an external heater. The metal heater ispreferably optically hidden under the black mask (BM). Therefore, thereis no reduction in LCD optical transmission and image luminance, noincrease in ambient light reflections, no degradation in image contrast,and no issues with heater electrical termination. Electrical terminationis preferably accomplished automatically with known TCP and anisotropicconductive film (ACF) termination. The TCP connection between the LCDand display electronics is advantageous as it provides a flexibleconnection.

Preferably, the heater pattern is comprised of a horizontal and verticalgrid of controlled resistance heater conductors, with low resistancehorizontal “heater+” bus bar at the top of the vertical grid (e.g.,preferably less than or equal to 0.5 ohms) and a low resistance“heater−” bus bar at the bottom of the vertical grid. It is preferredthat all portions of the heater grid be outside of the active pixelaperture and hidden from view under the black mask. The exact heatergrid pattern is located to minimize capacitive coupling between theheater grid and the gate and source bus lines. In the preferredembodiment, there are heater grid lines under each horizontal andvertical leg of the black mask.

Preferably, the heater grid is over-coated with an insulating dielectrichaving a breakdown potential of over 100 volts DC. Connections to theheater−(i.e., the bottom bus adjacent to the source TCPs) are preferablyrouted to associated traces on the source TCPs. Heater−is preferablyconnected, in the source PCB, to ground potential. Connections to theheater+(i.e., top bus bar or the bar on the edge opposite the sourceTCPs) are preferably routed to pads on the exposed areas of the frontside of the rear glass (i.e., TFT plate) for ACF connection to theheater and black mask EMI FPC. During heater operation, heater+ispreferably connected to 28 VDC through the heater and black mask EMIFPC. When the heater is not operating, the heater+connection ispreferably connected to heater−and ground.

In the preferred embodiment, all features of the patterned heater,including the heater+and heater−bars are covered by the black mask inthe assembled LCD cell so that no heater pattern or heater bus barfeatures are visible in the display image. FIG. 9 illustrates oneexample embodiment of a heater circuit of the present invention.

FIGS. 10A-B illustrate other integral heater designs. FIG. 10Aillustrates a vertical parallel heater design. In this embodiment, theheater conductors preferably lie directly under source bus lines. Theheater lines are preferably narrower than the bus lines and do notintrude into the sub-pixel apertures. This minimizes capacitive couplingto the pixel capacitor and eliminates reduction in panel transmission bythe heater. FIG. 10B illustrates one example grid design having 525horizontal and 525 vertical lines. In this embodiment, the heaterconductors preferably lie directly under source and gate bus lines andare narrower than the bus lines and do not intrude into the sub-pixelapertures. In alternate embodiments, the number of horizontal andvertical heater lines may vary. For example, the heater grid pattern maybe 525 horizontal and 1,573 vertical lines; 525 horizontal and 787vertical lines; or 768 half-width horizontal lines and 1,536 verticallines. In an alternate embodiment, the heater grid patterns may bevaried to provide a greater heater grid density around the periphery ofthe display. The heater grid density would decrease moving towards thecenter of the display. Placing a higher density grid pattern around theperiphery allows for the application of more heat around the edges ofthe display to account for the higher thermal mass due to the bezelattachment around the periphery of the display. In other words, due tothe bezel attachment, more heat is required around the periphery of thedisplay to achieve the same degree of display heating. Accordingly, thethermal rise of the display is substantially consistent for the edgesand center of the display.

As discussed, the integral metal heater of the present invention isapplied by known bus metallization techniques. FIG. 11 illustrates oneembodiment of a TFT design of the present invention with integralheater.

As shown in the embodiment illustrated in FIG. 4, it is also preferredthat thermal sensors 82 be placed on the inside portion of the glassplates. Preferably, the sensors are in close proximity to the heaterlayer to detect the heat being inputted into the liquid crystal layer soas to provide timely feedback to the system. The integral thermalsensors are also applied onto the TFT array layer preferably under theblack mask EMI layer. In this embodiment, thermal resistivity is reducedleading to faster thermal sensor and heater control response times.

The integral thermal sensor of the present invention provides anefficient, low cost solution as there are no separate thermal sensorcomponents that must be purchased. Furthermore, there is no process timeor labor required to attach a thermal sensor to the LCD or to attachthermal sensor wires to a circuit. With the integral thermal sensor,signal attachment automatically occurs with ACF attachment of the TCPattachment. The intimate contact between sensor and LCD fluid provideshigher accuracy and reduced time lag between actual fluid temperatureand thermal sensor readings.

In the preferred embodiment, a series/parallel array of diodes isembedded within the TFT array to sense the temperature of the LC fluid.FIG. 12 illustrates one embodiment of a diode array 88 of the presentinvention. In this embodiment, the thermal sensors are comprised of adiode array (e.g., 3 in series, 10 parallel) built into the TFT arraylayer.

The anodes of the top array are preferably connected to a common nodeand brought out of the source TCP as “Thermal Sensor+”. The cathodes atthe bottom of the diode array are preferably connected to common nodeand brought out of the source TCP as “Thermal Sensor−”.

The number of diodes in each array may vary, however in the preferredembodiment, the number of diodes shall be selected to provide a nominal2.5V to 5.0V change in the diode string forward bias potential as the LCfluid changes from −60 degrees C. to +100 degrees C.

In the preferred embodiment, a thermal sensor diode array according tothe present invention is located and electrically connected between eachsource TCP. For example, if there are four TCPs there will be threethermal sensor diode arrays. FIG. 13 illustrates a plan view of a flatpanel display showing thermal sensor placement.

FIG. 14 illustrates an example block diagram of the electricalcomponents and connections of a display incorporating the flat paneldisplay of the present invention.

Having shown and described a preferred embodiment of the invention,those skilled in the art will realize that many variations andmodifications may be made to affect the described invention and still bewithin the scope of the claimed invention. Thus, many of the elementsindicated above may be altered or replaced by different elements whichwill provide the same result and fall within the spirit of the claimedinvention. It is the intention, therefore, to limit the invention onlyas indicated by the scope of the claims.

1. A flat panel display comprising: a front plate; a rear plate; a layerof liquid crystals and a TFT array layer, both interposed between saidfront and rear plates; and at least one thermal sensor integral to theTFT array and hidden by an EMI layer to provide temperature sensing ofsaid layer of liquid crystals.
 2. A flat panel display according toclaim 1, wherein said at least one thermal sensor is comprised of anarray of diodes.
 3. A flat panel display according to claim 1, whereinthe at least one thermal sensor is applied onto the TFT array layer. 4.The flat panel display of claim 1, wherein: the thermal sensor providesa nominal 2.5 volt to 5.0 volt change in bias potential as the liquidcrystal temperature changes from −60 degrees Celsius to 100 degreesCelsius.
 5. The flat panel display of claim 1, wherein each at least onethermal sensor lies under the EMI layer.
 6. The flat panel display claim1, wherein the EMI layer is a black mask EMI layer.